Many commercially available products such as leaf blowers, blenders, etc. use small motors having an impeller mounted to a rotor. Vibration in such devices can be unpleasant, and in some cases, cause injury to the operator or damage to the device itself when excessive. The vibration in such devices arises principally from rotational imbalance in the impeller assembly. For example, as a rotating assembly revolves at a high speed, such as 15,000 rpm, any imbalance above about 0.6 gram inches causes unpleasant vibration.